Improvement of physicochemical properties of Fe2O3/MgO nanomaterials by hydrothermal treatment for dye removal from industrial wastewater

Three types of Fe2O3/MgO (FeMgOIM, FeMgOCo and FeMgOHy) nanomaterials were prepared by impregnation, co-precipitation and hydrothermal methods, respectively. The microporous FeMgO adsorbents were successfully used to remove synthetic textile dye (Remazol Red RB-133) by adsorption from aqueous solution. The as-prepared adsorbents were characterized by XRD, FT-IR, N-2 adsorption/desorption isotherms and TEM techniques. The results showed that a nanorod-like shape with high surface area and porous structure was obtained by hydrothermal treatment. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. The equilibrium adsorption data were best fitted by Langmuir isothermal model. The removal efficiencies of dye of 50 mg L-1 within 19 min can be ranked as: FeMgOHy > FeMgOIM > FeMgOCo. Also, the results indicated that pseudo-first-order and intra-particle diffusion models can better describe the adsorption kinetics. The microporous FeMgOHy and FeMgOIM were found to be effective adsorbent for the removal of dye from aqueous solution due to their increase in the microporosity as well as modified surface morphologies. The highly active FeMgOHy nanomaterial was evaluated for chemical oxygen demand (COD) and color reduction of a real industrial wastewater. A reduction in color and COD of 87% and 40%, respectively was achieved after 3 h from adsorption. (C) 2013 Elsevier B.V. All rights reserved.